use a infrared temp gun to check the temp of rad core top to bottom old magnet posted a reply about this just recently cant remember what the temp difference should be from memory it should only be a few degrees. its possible you have a partial blocked core.

wash the fins clean check fan belt tension and for flow in to tank (is water pump & thermostat working) also make sure the cooling system is properly bled of air air locks can cause hot spots.
to bleed the hydraulics you need to cycle the blade fully for a few seconds each way to remove air. if it really buzzes that is a sign of entrained air.

think i read in one of my Cat manuals that the differential temp of the rad from top to bottom only needs to be 15 degrees F (10 degrees C) maybe the minimum, not sure...

-that quite surprised me...not a lot...but the trick is to be able to remove the heat consistently, no matter what conditions...all kinds of loads, ambient temperatures, dust and debris, etc...

I had a new radiator installed in a JD 4440 years back and afterwards the temp would peg out on the top side after starting and then settle back. Come to find out the hot shot JD mechanic somehow got the wrong thermostat in backwards. Fought it for over a month and one day tore into it myself and found the problem. He even messed up the block heater.

I need to change the thermostat on my D4 but just haven't got to it yet. Engine runs too cool.

bursitis wrote:

so the fuel pressure stays up even when it bogs down? maybe adjust the fan belt and blow compressed air to clean out the radiator fins from dirt and debris. your main clutch is an oil clutch? how hot is the engine getting? on the gauge?

We ran it some more and paid close attention to what is going on. 

When we start it in the morning the fuel pressure is near the mark I made previously and the machine pushes fine. 
3-4 hours later it starts to wane and the temp gauge just touches the red. Fuel pressure drops at full RPM and the machine can barely do anything at that point. 

I did measure the clutch oil housing and found it to be a little cooler than the motor temp ... we were actually thinking it wasn't the motor temp but the clutch oil temp that was killing performance as in the past we had the machine pushing but overheating without pressure loss. 

When we run it next time I will check temp difference on core ... we did pull the core, clean it, seal it, reinstall etc not too long ago ... I also blew it out the other day but nothing impressive came out of it. The fan belt was adjusted to be a little tighter so it would be in spec according to the book and the airflow through the core seems substantially better after all of this. We also tested the thermostat and it was within spec. We did not open the airlock (I think if I recall it was in a tight spot up under the petcock / site glass for the pony motor) but I can do that ... does it need to be on to do this or can I keep it shutdown? We do still have a small radiator leak but we top off the fluid here and there ... someone suggested we use BARS flakes vs liquid to fix this. 

Cycling the the hydro does help ... I haven't noticed any issues since topping it off ... the frustrating part is knowing when it is "full" and when it isn't as you can barely see down into that tank :/ 

 

temp gauge touches the red? do you know at what temp the coolant has to be on that particular gauge to be at the red? is your gauge calibrated for your tractor specs??? probably the part number in the gauge face could be researched to answer this question. sounds like your tractor is overheating grossly. are the linings in your clutch the proper type for a wet clutch? probably.     fuel pressure will normaly drop with rpm loss.

the gauges that came on old cat equipment are really just idiot lights. but in reality what do you need to know whether it is in range or not and that is all that matters. but that then requires having the correct gauges installed. most vehicles are like this now too many just have a fault light. yes personally i prefer a actual reading.

for most engines the operating temp should be around 85 to 90 degrees celcius funnily enough 80 to 82 degrees is when most thermostats are set to open.

projectanavita wrote:

 
When we run it next time I will check temp difference on core ... we did pull the core, clean it, seal it, reinstall etc not too long ago ... I also blew it out the other day but nothing impressive came out of it. The fan belt was adjusted to be a little tighter so it would be in spec according to the book and the airflow through the core seems substantially better after all of this. We also tested the thermostat and it was within spec. We did not open the airlock (I think if I recall it was in a tight spot up under the petcock / site glass for the pony motor) but I can do that ... does it need to be on to do this or can I keep it shutdown? We do still have a small radiator leak but we top off the fluid here and there ... someone suggested we use BARS flakes vs liquid to fix this. 

Cycling the the hydro does help ... I haven't noticed any issues since topping it off ... the frustrating part is knowing when it is "full" and when it isn't as you can barely see down into that tank :/ 
 

 

it could still have some crud deep inside the cores which requires rodding to remove this must be done very gently or the core can become punctured.

if you can see the leak and access it the best is to flow a little solder over it fixing it pemanantly.

yes it can be bled without running the main but its best if you do have it idling as low as possible. yes the bleeder is on the pilot motor in a shit of a spot to get to on the pilot air cleaner side it screws into the top cover of the pilot motor. spray it liberally with penetrating fluid to free it up first. the best would be to replace the tap. work a bit of clear hose over the tap end so you can see any bubbles of air same idea as bleeding the brakes on the car. have the offsider slowly top off the rad until no more bubbles appear this may take a few goes to get all the air out.

the hydro oil should be visible in the bottom of the filler neck when running well thats how we did ours. after we re shafted the rams it took a few goes to get all the air out
 

Went to start Brutus today after sitting for 2 weeks as we were not in need of him. Started pony, cranked him over, and as soon as the main engine started oil and what we think water was coming out of the main oil vent on the motor right hand side ... Like pouring out. Shut him down and started to think about what fluid was in there and how it got there.

The fluid is more than half way up the stick 0__0 ... when we started him the last couple of weeks prior the mounting bolt for the radiator on the right hand side would spurt liquid when cranking the motor over ... we suspect the fluid is radiator fluid and are inquiring about a gasket kit for the head.

We haven't pulled the fluid yet to confirm it isn't diesel mixed in there instead.

i would say yes you have a bad head gasket, bad head, or bad liner seals or bad liners. or worst luck a combination of all of these.

has the reading on the fuel tank rod dropped since you parked it if it has then you may have fuel leaking where it shouldnt or some wayne kerr has been stealing fuel.
you will know by smell if the oil smells strongly of diesel chances are you have fuel getting into the sump.

to check if its water drain some out and let it settle for a couple of days if water the oil will float on top or it will be milkey or brown.
if fuel it will be thin and no colour change